Trailers used to haul loose materials such as dirt, sand, gravel, or grain commonly have beds or tubs that have an open top with generally vertical front and rear walls and sloping sidewalls for retaining contents within the trailer. Therefore, if the trailer bed is not covered as the trailer is pulled over the road, the loose contents may be blown and scattered out of the open top of the trailer bed. Additionally, the contents of the trailer bed may be compromised by rain, or other contaminants. Accordingly, it is known to deploy tarps (i.e. tarpaulin) across the open top space of the trailer beds to cover the contents of the trailer beds.
Several mechanisms have been devised for deploying the tarps across the trailer bed. Many of these devices include radial arms that are rotatably mounted at the front and rear of the tub and have a roll of tarp disposed between them. The tarp is rolled upon and supported by a roller or spindle. As the radial arms rotate in one direction across the truck bed, the roll of tarp between the arms is unrolled off of the roller to cover the contents of the truck bed. When the arms are rotated back in the opposite direction, the tarp is taken back up upon the roller to uncover the trailer bed. Examples of such devices may be seen in Bremer, U.S. Pat. No. 8,272,676; Searfoss, U.S. Pat. No. 6,206,449; and in Michel, U.S. Pat. No. 5,002,328.
The tarp rollers have traditionally been made from steel or aluminum. However, such rollers are notorious for bending and permanently deforming over time, or as the result of an impact against the roller. Such bent rollers result in lost time when the trailer can be used in hauling material and in significant expense in replacing the damaged rollers. The metal tarp rollers also suffer from being heavy and subject to corrosion. The metal rollers are also prone to damage during shipping. The metal rollers also typically require welding as part of their manufacturing process. This can make manufacturing and replacing the rollers expensive and inconvenient.